Flame Retardant Support Article

ABSTRACT

The invention relates to a flame retardant support article containing a support article comprising a resilient material and a flame retardant knit fabric at least partially surrounding the support article. The flame retardant knit fabric contains a plurality of yarns, wherein the yarns comprise flame retardant rayon fibers and polyester fibers. The plurality of yarns contains at least about 70% by weight flame retardant rayon fibers.

RELATED APPLICATIONS

This application claims priority to co-pending U.S. Provisional Patent Application 62/910,095 filed on Oct. 3, 2019, which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates support articles such as mattresses having flame retardant knit fabrics.

BACKGROUND

It is well known in the textile industry to produce flame retardant products for use in upholstered furniture, mattresses, foundations, automotive seating, public transportation seating, aircraft seating and the like, using fabrics containing fiberglass and/or modacrylic fibers. There is a need for low cost, but high performing barrier materials for use in support articles.

BRIEF SUMMARY

The invention relates to a flame retardant support article containing a support article comprising a resilient material and a flame retardant knit fabric at least partially surrounding the support article. The flame retardant knit fabric contains a plurality of yarns, wherein the yarns comprise flame retardant rayon fibers and polyester fibers. The plurality of yarns contains at least about 70% by weight flame retardant rayon fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates schematically one embodiment of an exemplary knit fabric being a rib knit.

FIG. 2 illustrates schematically one embodiment of a flame retardant support article being a mattress.

DETAILED DESCRIPTION

“Flame retardant” (abbreviated as FR in this patent application), in this application means a material that provides a thermal barrier and reduces body burn as described in NFPA 1971 and allows the user time to escape the flames and/or fire. Such a fiber, yarn, fabric, or article would preferably resist ignition and/or be self-extinguishing and/or create a char that prevents or retards burn-through to the mattress. In its preferred usage in the present application, the term “flame barrier” means a product incorporated into or on top of a composite article that when tested with a composite type test method, such as: CPSC (Consumer Product Safety Council) CFR 1633, California Test Bulletin 129 (TB 129) or California Test Bulletin 603 (TB603) for mattresses and foundations and California Test Bulletin 133 (TB 133) for upholstered furniture, the flame barrier allows for the continued use of conventional materials such as dress cover fabrics, fiber-fillings and polyurethane foams, while still passing these stringent large open flame tests. It is understood by someone skilled in the art that flame barriers made of the tubular knit flame barriers described in this invention, even at overall lower basis weights, can be made to pass less stringent open flame tests such California's Revised Test Bulletin 117 (TB 117—draft 02/02 version) and British Standard 5852.

Referring now to FIG. 2, there is illustrates a flame retardant support article 10 containing a support article 200 (in this illustration a mattress) at least partially surrounded by a flame retardant knit fabric 100 (part of the knit fabric 100 was removed in order to show lower layers in the Figure). The flame retardant knit fabric 100 preferably completely encapsulates the support article and may be used as a flame barrier to any suitable article.

The support article 200 may be any article providing support and optionally requiring flame resistance. Some examples of support articles 200 include, but are not limited to, upholstered furniture, mattresses, foundations, automotive seating, public transportation seating, aircraft seating, and the like. In one preferred embodiment, the support article is a mattress.

The flame retardant knit fabric 100 may be any suitable knit. A knit fabric is preferable due to its stretch ability and ease of manufacture. The flame retardant knit fabric 100 may be formed in any suitable manner and pattern. In one embodiment, the knit fabric is a tubular fabric and, in another embodiment, the knit fabric is a circular knit. These knits are advantageous for use as a barrier material for support articles such as mattresses as the knit would only require two seams to enclose the mattress.

In one preferred embodiment, the FR knit fabric 100 is a rib knit, more preferably a 2×1 rib knit. A 1×1 rib knit is shown in FIG. 1. In another embodiment, the FR knit fabric is a jersey knit fabric.

Preferably, the FR knit fabric has a weight of between about 3 and 15 ounces per square yard (oz/yd²). “About”, in this application, is defined to mean plus or minus five percent of the stated amount. of the Different weights of fabric can be achieved by using different denier yarns or double inserting the yarns (meaning that two yarns are used in the knitting process and are used in place of a single yarn).

Current knit socks for FR barriers contain fiberglass fibers and/or modacrylic fibers. Fiberglass fibers have traditionally been included for char strength (the strength of the knit fabric after it is burned), but is undesirable due to being itchy, scratchy, and an irritant. Modacrylics have traditionally been incorporated for FR properties but is undesirable due to the antimony and chlorine in the fibers. It was believed that one or both of these types of fibers were necessary for a successful FR knit fabric for a support article.

The flame retardant knit fabric 100 contains a plurality of yarns and these yarns contain a blend of polyester fibers and flame retardant rayon fibers (this means that the yarns contain an intimate blend of the fibers). The knit fabric (as a whole) contains at least about 70% wt flame retardant rayon fibers. Preferably the yarns are open end spun or ring spun.

In one embodiment, the knit fabric contains at least 75% wt FR rayon fibers and polyester fibers, more preferably at least about 80% wt. In another embodiment, the knit fabric contains at least 90% wt FR rayon fibers and polyester fibers, more preferably at least about 95% wt. In another embodiment, the knit fabric is essentially all contains at least 97% wt FR rayon fibers and polyester fibers, more preferably at least about 98% wt.

Preferably, the ratio between the FR rayon fibers and polyester fibers in the knit fabric is between about 1:1 to about 10:1, more preferably about 2:1 to 5:1. Preferably, all of the yarns in the FR knit fabric have the same fiber blend content (allowing for some amount of process variability). In another embodiment, at least some of the yarns within the FR knit fabric have a different ratio of fibers (as long as the knit fabric as a whole still meets the preferred ratios).

The average polyester staple length of the fibers is preferably between about 0.5 and 5 inches, more preferably between about 0.75 and 2.5 inches, more preferably about 1 to 2 inches. The average rayon staple length of the fibers is preferably between about 0.5 and 5 inches, more preferably between about 0.75 and 2.5 inches, more preferably about 1 to 2 inches. In one embodiment, the average staple length of the polyester fibers is within 50 to 150% of the average staple length of the rayon fibers.

Preferably, the fiberglass content of the knit fabric is as low as possible. In one embodiment, the knit fabric contains less than 5% wt, more preferably less than 3% wt, more preferably less than 1% wt. In one preferred embodiment, the knit fabric does not contain any intentionally added fiberglass fibers (meaning that no fiberglass fibers other than very small amounts of fiberglass contaminants would be in the knit fabric). In one embodiment, the knit fabric contains less than 0.5% wt, more preferably less than 0.1% wt fiberglass.

Preferably, the modacrylic content of the knit fabric is as low as possible. In one embodiment, the knit fabric contains less than 5% wt, more preferably less than 3% wt, more preferably less than 1% wt. In one preferred embodiment, the knit fabric does not contain any intentionally added modacrylic fibers (meaning that no modacrylic fibers other than very small amounts of fiberglass contaminants would be in the knit fabric). In one embodiment, the knit fabric contains less than 0.5% wt, more preferably less than 0.1% wt modacrylic.

The fibers in the FR knit fabric may contain additional treatments to impart desired characteristics. In one embodiment, the at least a portion of the fibers of the FR knit fabric comprise an anti-fungal treatment and/or antimicrobial treatment. In one embodiment, at least a portion of the fibers of the FR knit fabric contain a topical flame retardant treatment. In another embodiment, essentially none of the fibers of the FR knit fabric (defined as being less than about 1% wt of the fibers) has a topical flame retardant treatment. In one embodiment, at least a portion of the fibers in the FR knit fabric are colored. In another embodiment, at least a portion of the fibers in the FR knit fabric are treated with an anti-static treatment or other processing aid.

The size of the yarns in the FR knit fabric will vary depending on the particular fabric characteristics desired but is preferably within the range of from about 30/1 to 1/1 conventional cotton count, preferably from about 30/1 to 15/1 conventional cotton count.

Example 1

The FR knit fabric of Example 1 was made using yarns containing about 75% wt FR rayon staple fibers and 25% wt polyester staple fibers that were open end spun into yarns having a cotton count of about 24.5×1. The yarns were knitted in a circular knitted 2×1 rib knit fabric that had a weight of 3.7 oz/yd². The FR knit fabric contained no fiberglass fibers or modacrylic fibers.

The tubular knit sock was then cut to the length necessary to cover a 6″ thick all-foam twin size mattress, consisting of a 4″ base of standard polyurethane foam and a 2″ top layer of viscoelastic polyurethane foam and both ends of the mattress. One end of the tubular knit sock was seamed together to form a pocket closure seam. The knit tube sock was rolled up from the open end to the pocket closure end and placed on one end of the all-foam mattress. The knit tube sock was then rolled down the all-foam mattress and the open end was then sewn closed.

The above constructed mattress using the FR knit fabric of Example 1 was tested at the Milliken Pyro Analytical Center (Blacksburg, S.C.) according to CPSC CF %01633. The Peak Rate of Heat Release was 34.6 KW (maximum allowable rate of heat release is 200 KW) and the Total Heat Release was 3.0 MJ (maximum allowable in first 10 minutes is 15 MJ). This test was considered a significant pass of CPSC CFIG33.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A flame retardant support article comprising: a support article comprising a resilient material; and a flame retardant knit fabric at least partially surrounding the support article, wherein the flame retardant knit fabric comprises a plurality of yarns, wherein the yarns comprise flame retardant rayon fibers and polyester fibers, wherein the plurality of yarns comprises at least about 70% by weight flame retardant rayon fibers.
 2. The flame retardant support article of claim 1, wherein the amount of flame retardant rayon fibers and polyester fibers is at least about 95% by weight of the flame retardant knit fabric.
 3. The flame retardant support article of claim 1, wherein the amount of flame retardant rayon fibers and polyester fibers is at least about 98% by weight of the flame retardant knit fabric.
 4. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 3% of fiberglass fibers.
 5. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 1% of fiberglass fibers.
 6. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 0.1% of fiberglass fibers.
 7. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 3% of modacrylic fibers.
 8. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 0.1% of modacrylic fibers.
 9. The flame retardant support article of claim 1, wherein the flame retardant knit fabric comprises less than about 0.1% of fibers having a topical flame retardant treatment.
 10. The flame retardant support article of claim 1, wherein the flame retardant knit fabric is a circular knit.
 11. The flame retardant support article of claim 1, wherein the flame retardant knit fabric is a rib knit fabric.
 12. The flame retardant support article of claim 1, wherein the flame retardant knit fabric is a jersey knit fabric.
 13. The flame retardant support article of claim 1, wherein the yarns are open end spun.
 14. The flame retardant support article of claim 1, wherein the yarns have a flame retardant rayon fiber to polyester fiber ratio of about 2:1 to 5:1.
 15. The flame retardant support article of claim 1, wherein the flame retardant knit fabric has a weight of between about 3 and 15 ounces per square yard.
 16. The flame retardant support article of claim 1, wherein at least a portion of the yarns are double inserted in the flame retardant knit fabric.
 17. The flame retardant support article of claim 1, wherein the flame retardant knit fabric fully encapsulates the support article.
 18. The flame retardant support article of claim 1, wherein the support article is a mattress.
 19. The flame retardant support article of claim 1, wherein the support article comprising a resilient material is selected from the group consisting of a cushion, pillow, office panel, and seat.
 20. The flame retardant support article of claim 1, wherein the support article passes the 16 CFR 1633 Federal Open Flame Standard. 